/// 简化的集群引擎实现 - 用于验证编译
/// 
/// 这是一个简化版本的集群引擎，用于验证基础编译是否正常

use crate::{Error, Result};
use crate::sql::{QueryResult, Value};
use crate::sql::planner::LogicalPlan;
use super::{ClusterConfig, ClusterState, ClusterHealth, ClusterEvent};
use std::collections::HashMap;
use std::sync::Arc;
use parking_lot::RwLock;
use std::time::{Instant, SystemTime};
use std::sync::atomic::{AtomicU64, AtomicBool, Ordering};

/// 简化的集群引擎
#[derive(Debug)]
pub struct SimpleClusterEngine {
    /// 集群配置
    config: ClusterConfig,
    /// 集群状态
    cluster_state: Arc<RwLock<ClusterState>>,
    /// 查询计数器
    query_counter: AtomicU64,
    /// 是否为领导者
    is_leader: AtomicBool,
}

impl SimpleClusterEngine {
    /// 创建新的简化集群引擎
    pub fn new(config: ClusterConfig) -> Result<Self> {
        tracing::info!("创建简化集群引擎，集群名称: {}, 节点ID: {}", 
                      config.cluster_name, config.node_id);
        
        // 创建集群状态
        let cluster_state = Arc::new(RwLock::new(ClusterState {
            cluster_id: format!("cluster_{}", config.cluster_name),
            current_term: 0,
            leader_id: None,
            active_nodes: 0,
            health_status: ClusterHealth::Healthy,
        }));
        
        Ok(Self {
            config,
            cluster_state,
            query_counter: AtomicU64::new(0),
            is_leader: AtomicBool::new(false),
        })
    }
    
    /// 启动集群引擎
    pub async fn start(&self) -> Result<()> {
        tracing::info!("启动简化集群引擎: {}", self.config.cluster_name);
        Ok(())
    }
    
    /// 停止集群引擎
    pub async fn stop(&self) -> Result<()> {
        tracing::info!("停止简化集群引擎");
        Ok(())
    }
    
    /// 执行集群查询
    pub async fn execute_cluster_query(&self, plan: LogicalPlan) -> Result<QueryResult> {
        let start_time = Instant::now();
        let query_id = self.query_counter.fetch_add(1, Ordering::SeqCst);
        
        tracing::info!("开始集群查询 #{}: {:?}", query_id, plan);
        
        // 简化实现：返回空结果
        let result = QueryResult::new(
            vec![],
            vec!["id".to_string(), "name".to_string()],
            0,
            start_time.elapsed().as_millis() as u64,
        );
        
        Ok(result)
    }
    
    /// 获取集群配置
    pub fn get_config(&self) -> &ClusterConfig {
        &self.config
    }
    
    /// 获取集群状态
    pub fn get_cluster_state(&self) -> ClusterState {
        self.cluster_state.read().clone()
    }
    
    /// 是否为领导者
    pub fn is_leader(&self) -> bool {
        self.is_leader.load(Ordering::SeqCst)
    }
    
    /// 设置领导者状态
    pub fn set_leader(&self, is_leader: bool) {
        self.is_leader.store(is_leader, Ordering::SeqCst);
        tracing::info!("节点 {} 领导者状态: {}", self.config.node_id, is_leader);
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::net::SocketAddr;
    
    #[tokio::test]
    async fn test_simple_cluster_engine_creation() {
        let config = ClusterConfig {
            cluster_name: "test-cluster".to_string(),
            node_id: "node-1".to_string(),
            listen_addr: "127.0.0.1:8001".parse::<SocketAddr>().unwrap(),
            seed_nodes: vec![],
            replication_factor: 1,
            heartbeat_interval_ms: 1000,
            election_timeout_ms: 5000,
        };
        
        let cluster_engine = SimpleClusterEngine::new(config).unwrap();
        
        // 验证配置
        let engine_config = cluster_engine.get_config();
        assert_eq!(engine_config.cluster_name, "test-cluster");
        assert_eq!(engine_config.node_id, "node-1");
        
        // 验证状态
        let cluster_state = cluster_engine.get_cluster_state();
        assert_eq!(cluster_state.cluster_id, "cluster_test-cluster");
        assert_eq!(cluster_state.current_term, 0);
        
        // 验证领导者状态
        assert!(!cluster_engine.is_leader());
        cluster_engine.set_leader(true);
        assert!(cluster_engine.is_leader());
    }
    
    #[tokio::test]
    async fn test_simple_cluster_engine_lifecycle() {
        let config = ClusterConfig {
            cluster_name: "lifecycle-test".to_string(),
            node_id: "node-1".to_string(),
            listen_addr: "127.0.0.1:8002".parse::<SocketAddr>().unwrap(),
            seed_nodes: vec![],
            replication_factor: 1,
            heartbeat_interval_ms: 1000,
            election_timeout_ms: 5000,
        };
        
        let cluster_engine = SimpleClusterEngine::new(config).unwrap();
        
        // 测试启动和停止
        cluster_engine.start().await.unwrap();
        cluster_engine.stop().await.unwrap();
    }
    
    #[tokio::test]
    async fn test_simple_cluster_query() {
        let config = ClusterConfig {
            cluster_name: "query-test".to_string(),
            node_id: "node-1".to_string(),
            listen_addr: "127.0.0.1:8003".parse::<SocketAddr>().unwrap(),
            seed_nodes: vec![],
            replication_factor: 1,
            heartbeat_interval_ms: 1000,
            election_timeout_ms: 5000,
        };
        
        let cluster_engine = SimpleClusterEngine::new(config).unwrap();
        
        // 测试查询执行
        let scan_plan = LogicalPlan::TableScan {
            table_name: "test_table".to_string(),
            alias: None,
            projection: None,
        };
        
        let result = cluster_engine.execute_cluster_query(scan_plan).await.unwrap();
        assert_eq!(result.column_names.len(), 2);
        assert_eq!(result.column_names[0], "id");
        assert_eq!(result.column_names[1], "name");
    }
}
